HOT SPELL SETS NEW RECORD-BREAKING TEMPERATURES FOR JAMAICA

WHY WAS THIS SUMMER SO HOT?

Meteorological Service of Jamaica

August 2019

Hot spell sets new record-breaking temperatures for Jamaica

If you thought this summer felt really, really hot, you were right. Both June and July 2019 were the hottest June and July on record for the globe and here in Jamaica, this was no different. Scientists are already saying that this summer is one for the history book. Globally, the average temperatures were the hottest June and July on record, with June temperatures ranging about 0.10°C (or 0.18°F) higher than that of the previous record-holder, of June 2016. Based on data coming out of the US National Oceanic and Atmospheric Administration (NOAA), the average global temperature was 0.94°C (1.7F) warmer than the 20th Century average.

Based on preliminary data from the World Meteorological Organization, July 2019 may have been the single hottest month in recorded history. Also, the European Union’s Copernicus Climate Change Programme, which analyses temperature data from around the planet, said that this July was around 0.56 °C warmer than the global average temperature between 1981-2010.

Three years ago, the earth recorded its warmest June and July ever, followed by a strong El Niño event, (warming of the ocean surface in the central and eastern tropical Pacific Ocean), according to data provided by the comprehensive climate information centre for the European Union. Although a strong El Niño event during 2019 appears unlikely, through the September-November season of 2019, the development of La Niña is extremely unlikely. El Niño events are generally associated with reduced rainfall and warmer than normal air temperatures across the western Caribbean including Jamaica.

Summer had barely begun here in Jamaica, but temperature records were already being broken. Data recently collected from several stations across the island indicated that temperatures for June 2019 were higher than for any other June on record. In fact, extreme maximum temperatures in some cases were more than 1.0°C above what they were 2016 and 2018 this time for the month of June, and it has become the hottest June ever recorded for Jamaica.

While not as persistent as that of summer 2016, where several extreme heat events were reported across the globe. These short hot spells, caused by a mass of hot and dry air coming from the Sahara Desert coupled with a persistently strong high-pressure system across the region and stronger winds (which act as the transport for the dust), was enough to intensify the heat across Jamaica and the Caribbean. The six days (June 17-22) were of unusually high temperatures. Little or no cloud cover, resulted in days with record-breaking temperatures, especially over eastern parishes. This led to the month as a whole was around 1.5-3°C above the previous record for June, set in 2016, and about 3-6°C higher than expected from the trend in recent decades.

Although it is difficult to directly attribute these hot spells to climate change, such extreme weather events are expected to become more common as the planet continues to warm under increasing greenhouse gas concentrations. Some gases, including carbon dioxide and methane, trap heat in the Earth’s atmosphere, producing a “greenhouse effect” which keeps the planet at a comfortable temperature however human activities have expanded this greenhouse effect through significant emissions of these gases and this has resulted in warmer than normal temperatures. Climate scientists say that our globe is 1°C hotter today than it was between 1850 and 1900 and that this is due in part to gas emissions from cars, planes and other human activities.

Average temperatures may be unprecedented in 2019, but the weather extremes seen in Jamaica are changing character. Along with most of the eastern parishes in Jamaica, the country is experiencing more unusually hot days and nights and fewer extremely cool days and nights, the UWI Climate Study Group, Mona reported recently. Heavy downpours are also becoming more frequent in some areas, while droughts also turn more severe and more frequent in some sections.

Based on a recent report by the Caribbean Sustainability Network, Kingston, Jamaica is on track to be the second city in the world to reach its climate departure by 2023. The report also stated that based on current projections (from a study out of the University of Hawaii led by biologist Camilo Mora) the tropics will be at the epicentre of global warming and will bear the brunt of the initial related changes in global temperatures. According to the report, this raises concerns for water scarcity, changes in the food supply, social and health issues from the increased spread of infectious diseases, heat stress, conflicts related to scarce resources and a variety of other economic challenges that countries like Jamaica could face in the near future.

During the month of June and July, firefighters across the island were busy battling bushfires across several parishes due to the high temperatures and dry conditions from the lack of rainfall. Based on information coming out of the Jamaica Fire Brigade, firefighters had responded to over 280 calls in St Mary alone during the months of June and July. The majority of the calls would have been for bush fires. Throughout the month of June 2019, extreme temperatures across Jamaica increased significantly in some areas when compared to those of last year; due to the presence of the Saharan dust, reduced cloud cover and a very strong high-pressure system, especially during the 2nd half of the month.

Data collected from fourteen stations across the island were examined. The data showed that all stations recorded higher extreme temperatures in June and July 2019 when compared to June and July 2018 (4th warmest year globally on record) and June and July 2016 (warmest year globally on record). In some cases, the extreme temperatures had increased by as much as 3.6 degrees Celsius over the previous year. The data also indicated that the highest maximum temperature recorded during the period was 39.1 degree Celsius. This was recorded in St. Andrew at our Shortwood Teacher’s College weather station on Saturday, June 22. Meanwhile, New Forrest in Manchester recorded the largest difference in temperature of 3.6 degrees Celsius when compared to the same time last year.

Station

Parish

Daytime Extreme Temperatures

(June 2016)

Daytime Extreme Temperatures

(June 2018)

Daytime Extreme Temperatures

(June 2019)

Frome

Westmoreland

35.4

34.3

35.8

Santa Cruz

St. Elizabeth

n/a

36.2

38.1

New Forrest

Manchester

36.9

34.9

38.5

May Pen

Clarendon

35.6

34.8

36.7

Bodles

St Catherine

35.7

34.6

36.6

Manley

KSA

33.5

33.8

34.6

Shortwood T.C.

KSA

37.2

36.0

39.1

Serge Island

St Thomas

n/a

33.6

34.7

Fair Prospect High

Portland

35.1

36.1

36.6

Orange River

St Mary

32.2

32.2

33.4

Bengal Farm

St Ann

34.2

32.9

35.0

Pantrepant Farm

Trelawny

34.1

34.7

36.4

Sangster

St James

34.4

35.2

35.6

Rhodes Hall

Hanover

n/a

32.9

34.1

Legend

Figures in red are significantly higher than last year (by as much as 1.0 degrees Celsius or more)

Table 1: June Temperature Comparison Chart.

Station

Parish

Daytime Extreme Temperatures

(July 2016)

Daytime Extreme Temperatures

(July 2018)

Daytime Extreme Temperatures

(July 2019)

Frome

Westmoreland

35.8

34.9

34.2

Santa Cruz

St. Elizabeth

n/a

36.6

36.5

New Forrest

Manchester

37.0

37.1

36.8

May Pen

Clarendon

35.5

35.7

36.5

Bodles

St Catherine

35.8

34.8

34.7

Manley

KSA

35.5

34.6

34.7

Shortwood T.C.

KSA

38.0

36.6

37.8

Serge Island

St Thomas

n/a

35.1

36.4

Fair Prospect High

Portland

35.7

36.5

36.1

Orange River

St Mary

33.7

33.4

n/a

Bengal Farm

St Ann

33.7

34.3

35.6

Pantrepant Farm

Trelawny

35.9

34.7

36.0

Sangster

St James

35.0

35.6

35.5

Rhodes Hall

Hanover

n/a

32.9

34.0

Legend

Figures in red are significantly higher than last year (by as much as 1.0 degrees Celsius or more)